In general, a portable terminal is a device, commonly called a mobile communication terminal such as a digital phone, cellular phone, PCS phone, etc., or portable digital terminal such as a personal digital assistant (PDA), a small-sized notebook computer, etc. Typically, it is connected with a wireless communication link for providing various digital content such as audio and image information to users.
Portable terminals have been improved with the aim of high sensitivity and size/weight reduction for maximizing portability, and this trend may be found when we see how mobile communication terminals, representative of such portable terminals, have been developed.
In other words, bar-type or flip-type terminals among early mobile communication terminals are rarely used because such terminals have difficulty in dimensional expansion as well as relatively large size and weight. Sliding folder-type or folder-type terminals are widely used due to small size and weight as well as dimensional expansion capability.
On the other hand, wireless data services are becoming popular and there is a general trend that multimedia content providing functions of portable terminals are becoming more important than classical functions provided by such portable terminals, such as telephone call functions in case of mobile communication terminal, and data input functions in case of PDAs.
In order to achieve such multimedia content providing functionality, and in particular image content providing functionality point an important factor is how well image content received from a communication network is displayed through a display panel or unit of a portable terminal.
As mentioned above, however, current portable terminals are aiming to be small size and light weight. Accordingly, there exists a problem that content including high quality images cannot be displayed on the portable terminal due to the restricted size of a conventional display panel thereof.
Hereinafter, dual display panel folder-type terminal having the most developed and popularized shape among conventional portable terminals will be described with the problem of the display panel structure.
FIG. 1 and FIG. 2 are perspective views respectively illustrating an external shape seen from the inside or the outside when a dual display panel folder-type terminal having two display panels is unfolded. And FIG. 3 is a block diagram showing a module structure in the terminal shown in FIG. 1 and FIG. 2.
As shown in FIG. 1 and FIG. 2, dual display panel folder-type terminal 10 includes a main body 20 and a folder 30 combined with the main body 20 in such a manner that the folder 30 is open or closed through a hinge, and main display panel 31 and sub-display panel 32, each of which is a liquid crystal screen, are provided at the inner and outer surface of the folder 30 respectively.
Furthermore, the display module includes the main display panel 31, a main scan driver 41, a main data driver 40, a main display panel controller 42, the sub-display panel 32, a sub-scan driver 51, a sub-data driver 50, and a sub-display panel controller 52, as shown in FIG. 3.
Here, scan drivers 41, 51 and data drivers 40, 50, as mentioned above, mean circuit devices for driving the rows and columns of an FPD (Flat Panel Display) in which light-emitting devices such as LCD, PDP, OLED or the like are arranged in rows and columns, and operated in the form of a matrix. Sometimes the scan drivers 41, 51 are called gate drivers, and data drivers 40, 50 are called source drivers.
The main display panel 31 has pixels arranged in a matrix form having a plurality of row lines and column lines, and is controlled by main scan driver 41, main data driver 40, and main display panel controller 42.
Furthermore, main scan driver 41 scans row lines (Y-axis) of main display panel 31 sequentially, and main data driver 40 converts an image data into electrical voltage or current, and applies it to the column lines (X-axis) of main display panel 31.
Main display panel controller 42 controls the main data driver 40 and main scan driver 41 by providing them with image data signals and scan signals, respectively.
On the other hand, sub-display panel 32, sub-scan driver 51, sub-data driver 50 and sub-display panel controller 52 will individually perform the same function as that of the above-mentioned main display related modules 31, 41, 40, 42.
However, main display panel 31 and sub-display panel 32 of the dual display panel folder-type terminal 10 are mounted on the inner and outer sides of the folder 30, respectively, in an independent manner, and have no mutual link function with each other. Typically, the main display panel 31 is wholly responsible for multimedia content display function, and the sub-display panel 32 performs only a simple function such as guidance window display.
Accordingly, it is impossible to provide a sufficient screen size and an ideal aspect ratio of 16:9 because the size of main display panel 31 is restricted by the size of the folder 30.
In other words, the size of main display panel 31 of the folder 30 is small, so it has difficulty in displaying detail parts of image. Also, in case that a large screen image such as high definition television (HDTV) multimedia content having the ratio 16:9 is to be displayed, the original 16:9 screen image cannot be supported. Accordingly, the image must be adjusted to the shape of main display panel 31 of the portable terminal 10, so there is a problem in which digital content reproducibility decreases remarkably and the shape of screen is changed.
Furthermore, even in the display module construction, display panel controllers 42, 52 for controlling panels 31, 32 are respectively connected to main display panel 31 and sub-display panel 32, so another problem is the relatively large circuit area required for such duplicate circuits and the associated power consumption
Therefore, there is a need for large screen display devices which are capable of displaying large screen images with an aspect ratio 16:9 on mobile communication terminals or small-sized portable terminals such as PDAs or the like.